I am the inheritor of some old radios that have been passed down in the family, going back to a radio which must have been purchased by my grandfather around 1927. That RCA Radiola 17 radio is described here. I recently got this radio working again, likely for the first time since about 1935. This paper describes the journey, both the repairs made and some analysis of how it now performs. This radio was the first of RCA's plug-in radios; earlier radios had to work off of batteries. It took quite a few batteries, something like 10, to power the earlier and quite similar Radiola-16. Radio technology was developing rapidly.
Below is a presentation given at Wilkes university on March 21, 2023 on early radios. This includes some material on early radios of the 1900 to 1940 era, then developments afterward. The progress is illustrated by three radios from my family history. The Radiola 17, dating to 1927, is the earliest. It is not superheterodyne, as most radios are after 1930 or so. This radio was replaced by a large console model in the around 1930 or later, which seems to have disappeared except for the cabinet. The Hallicrafters D-20 radio, dating to 1939, was purchased by my father on Guam during World War 2, likely in 1945. I recall using it myself about 1963 and after. It has lots of big improvements, such as AGC, Superheterodyne, BFO, and four different bands. Unlike the Radiola 17, it could be aligned to give good performance. The third radio, a common Emerson All American Five (AA5) type, reduces the complexity and cost to allow mass production at a low price. This particular radio from 1949 was in our dining room. We would listent to radio shows such as The Shadow and Johnny Dollar, as well as news and editorial - Fulton Lewis Jr. That's as much as I recall. You won't hear those now! Of course, Radio developed much further later, but this short 1927 to 1949 era showed an amazingly rapid transition of technology that is interesting.
Early Radio presentation of March 21, 2023
An even erlier radio was given to me on the occasion of making the "Early Radio" presentation above. Actually, Mr. Robert Taylor gave me five of them that his father had worked on as a hobby. These were five Crosley radios from about 1924, including a one-tube radio, two two-tune radios, and two three tube radios. All were somewhat in need of repair. But, they were particularly interesting as all featured "Regenerative" detectors. In a regererative detector, positive feedback is used to boost the amplification factor, potentially quite a bit. That technique also features the possibility of too much feedback, resulting in a loud unpleasant squeal. I had never encountered a commercial regenerative radio before. When I was a child, I did have a one tube electronics kit in which one of the projects was a regenerative detector radio, so I had seen and was familiar with the concept. So, the goal of my project was to get one of these early radios working, and see what the experience of using it was like. The paper below describes the process of doing so, up to the point where I was able to actually receive a radio station and hear it through a speaker. There is more yet to be done. I'd like to push the amplifier B+ supply from 45V up to 90V, and also get a couple of the other radios in this set of five working as well. So, this is an unfinished project, with the paper marked as "Draft" for that reason. If I have occasion to do the "Early Radios" presentation again, this radio will be part of it.
